JP2013038524A - Piezoelectric device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece and a piezoelectric device, in which electrodes are formed on one principal surface of a base plate, and no electrode is formed on the other principal surface.SOLUTION: A piezoelectric device (100) includes: a piezoelectric vibration piece (130a) having an excitation electrode (131) and an extraction electrode (132); a base plate (120a) composed of glass or a piezoelectric material and having a mounting face and a bonding face (122), in which castellations (127) recessed inward from a side face from the mounting face to the bonding face are formed; and a non-conductive bonding material (140) for bonding the piezoelectric vibration piece and the base plate. The castellation has a first face (127a) extending from the mounting face to a side of the bonding face, and a second face (127b) extending outward from the bonding face to the mounting face and having an area less than that of the first face, in which a wiring electrode (128) formed on the first face, the second face and a side face of the bonding material extends from an external electrode (125) to the extraction electrode in the same electrode layer as the external electrode.

Description

  The present invention relates to a piezoelectric device and a method for manufacturing a piezoelectric device. In particular, the present invention relates to a piezoelectric device in which a wiring electrode formed in a castellation extends to an extraction electrode of a piezoelectric piece via a side surface of a bonding material, and a manufacturing method thereof.

  There is known a piezoelectric device in which a piezoelectric vibrating piece that vibrates at a predetermined frequency is sandwiched between a base plate and a lid plate. In such a piezoelectric device, a castellation is formed on the side surface of the base plate, and the mounting terminal and the excitation electrode are electrically connected via the wiring electrode formed on the castellation.

  For example, Patent Document 1 discloses a piezoelectric device in which a through hole is formed in a base plate, and electrodes formed on the front and back surfaces of the base plate are electrically joined to each other through electrodes formed in the through hole. By forming the through hole by etching from the front and back surfaces of the base plate, the intermediate portion of the through hole protrudes to the outside of the base plate, that is, the diameter of the intermediate portion of the through hole is formed small. Regarding the castellation, like the through hole, the middle part of the castellation protrudes outside the base plate. Therefore, the castellation has a surface facing the front side direction and a surface facing the back side direction of the base plate. Therefore, the electrode formed in the castellation is formed by performing sputtering or vacuum deposition from both the front and back sides of the castellation.

JP-A-6-343017

  On the other hand, it is desirable that the manufacturing process of the piezoelectric device be simplified, and an expensive metal may be used for the electrode material, and it is desirable to reduce the amount of use. If sputtering or vacuum deposition or the like is performed from one main surface to the base plate castellation, the manufacturing direction can be simplified and the amount of electrode material used can be reduced.

  Therefore, the present invention provides a piezoelectric device in which an external electrode and a wiring electrode to an extraction electrode of a piezoelectric vibrating piece are formed by sputtering or vacuum deposition, and a method for manufacturing the piezoelectric device.

  A piezoelectric device according to a first aspect includes a piezoelectric vibrating piece having a pair of excitation electrodes and a pair of extraction electrodes drawn from the pair of excitation electrodes, a bonding surface having a mounting surface having a pair of external electrodes and the piezoelectric vibrating piece. A base plate made of glass or a piezoelectric material on which a pair of castellations recessed from the side surface extending from the mounting surface to the bonding surface is formed, and between the piezoelectric vibrating piece and the base plate, A non-conductive bonding material for bonding the piezoelectric vibrating piece and the base plate, the pair of castellations extending outward from the mounting surface to the bonding surface side, and outward from the bonding surface to the mounting surface A wiring electrode formed on the first surface, the second surface, and the side surface of the bonding material, with the same electrode layer as the external electrode, and an extraction electrode from the external electrode. It extends to.

  In the first aspect, the piezoelectric device according to the second aspect has a pair of castellations between the first surface and the second surface, the first surface and a projecting surface protruding beyond the base plate from the second surface.

  In the piezoelectric device according to the third aspect, in the first aspect and the second aspect, the wiring electrode is formed in the central region of the castellation, and the end of the castellation where the castellation and the side surface of the base plate are in contact Glass or piezoelectric material is exposed.

  According to a fourth aspect of the piezoelectric device, from the first aspect to the third aspect, the base plate has a rectangular shape having a long side and a short side, and the castellation extends in the short side direction only on the short side or the short side and the long side. It includes a shape extending in the short side direction from the corner where the side intersects.

  According to a fifth aspect of the present invention, there is provided a method of manufacturing a piezoelectric device using a base wafer having a plurality of base plates each having a mounting surface on which external electrodes are formed and a bonding surface opposite to the mounting surface. The base wafer is made of glass or a piezoelectric material, and a through hole is formed in which the diameter decreases from the mounting surface to the intermediate portion separated by the first distance and increases from the intermediate portion to the bonding surface separated by the second distance shorter than the first distance. A step of preparing a base wafer, a step of preparing a piezoelectric wafer having an excitation portion having an excitation electrode, a frame portion surrounding the excitation portion, an extraction electrode drawn from the excitation electrode to the frame portion, and a through hole and an extraction electrode A bonding process for bonding the base wafer and the piezoelectric wafer with a bonding material so as to overlap, and an external electrode and a wiring electrode extending from the external electrode to the extraction electrode through the side surface of the through hole and the side surface of the bonding material And a wiring forming step of forming a.

  According to a sixth aspect of the method for manufacturing a piezoelectric device, in the fifth aspect, in the wiring formation step, the first opening corresponding to the external electrode and the second opening corresponding to the wiring electrode are narrower than the through hole on the mounting surface of the base wafer. A wiring electrode is formed by sputtering or vacuum deposition.

  According to the present invention, a piezoelectric device can be manufactured by a simple manufacturing method by performing sputtering or vacuum deposition from one main surface.

1 is an exploded perspective view of a piezoelectric device 100. FIG. (A) is sectional drawing of the AA cross section of FIG. (B) is a plan view of the base plate 120a. (C) is a plan view of the base plate 120a on which the external electrode 125 and the ground terminal 126 are shown. 3 is a flowchart illustrating a method for manufacturing the piezoelectric device 100. It is a top view of the piezoelectric wafer W130. It is a top view of the base wafer W120. 6 is a flowchart showing a method for manufacturing the base wafer W120 shown in FIG. 6 is a flowchart showing a method for manufacturing the base wafer W120 shown in FIG. (A) is the fragmentary sectional view of the wafer to which the piezoelectric wafer W130 and the base wafer W120 were mutually joined. FIG. 5B is a partial cross-sectional view of the wafer in which the piezoelectric wafer W <b> 130 and the lid wafer W <b> 110 are bonded. (C) is a partial cross-sectional view of a wafer in which electrodes are formed on the base wafer W120. 2 is an exploded perspective view of a piezoelectric device 200. FIG. (A) is sectional drawing of CC cross section of FIG. (B) is a plan view of the base plate 220. FIG. 6C is a plan view of the base plate 220 on which the external electrode 225 and the ground terminal 226 are shown. It is a top view of the piezoelectric wafer W230. It is a top view of the base wafer W220. 13 is a flowchart showing a method for manufacturing the base wafer W220 shown in FIG. 13 is a flowchart showing a method for manufacturing the base wafer W220 shown in FIG. 13 is a flowchart showing a method for manufacturing the base wafer W220 shown in FIG. (A) is the fragmentary sectional view of the wafer to which the piezoelectric wafer W230 and the base wafer W220 were joined mutually. FIG. 4B is a partial cross-sectional view of the wafer in which the piezoelectric wafer W230 and the lid wafer W110 are bonded. (C) is a partial cross-sectional view of a wafer in which electrodes are formed on a base wafer W220. (A) is a plan view of the surface at the −Y′-axis side of the base wafer W <b> 220 on which the electrodes are formed. FIG. 17B is an enlarged plan view of a region 171 in FIG. (A) is a perspective view of the base plate 320. FIG. FIG. 6B is a plan view of the base plate 320 on which the external electrode 325 and the ground terminal 326 are shown. FIG. 6C is a partial plan view of the surface on the −Y′-axis side of the base wafer on which the base plate 320 is formed. (A) is a perspective view of the base plate 420. FIG. FIG. 6B is a plan view of the base plate 420 on which the external electrode 425 and the ground terminal 426 are shown. (C) is a partial plan view of the surface on the −Y′-axis side of the base wafer on which the base plate 420 is formed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

(First embodiment)
<Configuration of Piezoelectric Device 100>
FIG. 1 is an exploded perspective view of the piezoelectric device 100. The piezoelectric device 100 is a surface-mount type piezoelectric device, and is used by being mounted on a printed circuit board or the like. The piezoelectric device 100 is mainly composed of a lid plate 110, a base plate 120a, and a piezoelectric vibrating piece 130a. The lid plate 110 is made of, for example, ceramic, glass, or a piezoelectric material, and the base plate 120a is made of, for example, a piezoelectric material such as a quartz material. Further, for example, an AT-cut quartz material is used for the piezoelectric vibrating piece 130a. In the AT-cut quartz crystal material, the main surface (YZ plane) is inclined 35 degrees 15 minutes from the Z axis in the Y axis direction with respect to the Y axis of the crystal axis (XYZ). In the following description, the new axes tilted with respect to the axial direction of the AT-cut quartz material are used as the Y ′ axis and the Z ′ axis. That is, in the piezoelectric device 100, the long side direction of the piezoelectric device 100 is described as the X-axis direction, the height direction of the piezoelectric device 100 is defined as the Y′-axis direction, and the direction perpendicular to the X and Y′-axis directions is described as the Z′-axis direction.

  The base plate 120a is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. The surface on the −Y′-axis side of the base plate 120a is charged with an external electrode 125, which is an electrode for electrically connecting the piezoelectric device 100 to a printed circuit board or the like via solder, and static electricity charged on the piezoelectric device 100. This is a mounting surface on which a ground terminal 126 for removal is formed. The base plate 120a is bonded to the piezoelectric vibrating piece 130a by applying a non-conductive bonding material 140 (see FIG. 2) to the bonding surface 122 which is the surface on the + Y′-axis side. Further, the base plate 120a is formed with a recess 123 that is recessed from the joint surface 122 in the −Y′-axis direction, and the −Z′-axis side on the −X-axis side and the −X-axis side − of the base plate 120a. A castellation 127 that is recessed inside the base plate 120a is formed on the side surface of the corner portion on the Z′-axis side. Each castellation 127 is provided with a wiring electrode 128, and the wiring electrode 128 is electrically connected to the external electrode 125.

  The lid plate 110 is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. On the surface at the −Y′-axis side of the lid plate 110, a bonding surface 112 is formed that is bonded to the piezoelectric vibrating piece 130 a via the bonding material 140 (see FIG. 2). Further, the lid plate 110 is formed with a recess 111 that is recessed from the joint surface 112 in the + Y′-axis direction.

  The piezoelectric vibrating piece 130a includes an excitation part 133 that vibrates at a predetermined frequency, a frame part 134 that is formed so as to surround the excitation part 133, and a connection part 135 that connects the excitation part 133 and the frame part 134 to each other. ,have. In addition, a through groove 136 that penetrates the piezoelectric vibrating piece 130 a in the Y′-axis direction is formed in a region other than the coupling portion 135 between the excitation portion 133 and the frame portion 134. Further, excitation electrodes 131 are formed on the surfaces of the excitation unit 133 on the + Y′-axis side and the −Y′-axis side, respectively. From the excitation electrode 131 formed on the + Y′-axis side, the connecting portion 135 formed on the −X-axis side and the side surface of the through-groove 136 on the −Z-axis side on the −Z′-axis side of the frame portion 134. The extraction electrode 132 is extended to the corner of the surface on the −Y ′ axis side on the −Z axis side on the −X axis side. Further, from the excitation electrode 131 formed on the −Y′-axis side, −Z on the + X-axis side of the surface on the −Y′-axis side of the frame portion 134 through the connecting portion 135 formed on the + X-axis side. 'The extraction electrode 132 is extracted to the corner on the axis side.

  FIG. 2A is a cross-sectional view taken along the line AA in FIG. In the piezoelectric device 100, the bonding surface 122 of the base plate 120 a and the surface on the −Y′-axis side of the frame portion 134 of the piezoelectric vibrating piece 130 a are bonded via a non-conductive bonding material 140, and the bonding surface of the lid plate 110. 112 and the surface on the + Y′-axis side of the frame portion 134 of the piezoelectric vibrating piece 130 a are bonded together via a non-conductive bonding material 140. As the bonding material 140, for example, a low-melting glass which is a glass bonding material having a melting point of 500 degrees or less, a resin bonding material such as a polyimide resin, or the like is used. The castellation 127 of the base plate 120a includes a first surface 127a extending outward from the surface on the −Y′-axis side of the base plate 120a toward the joining surface 122 side of the base plate 120a, and −Y ′ of the base plate 120a from the joining surface 122. A second surface 127b that extends outward to the shaft-side surface and is narrower than the area of the first surface 127a. That is, the normal vector of the first surface 127a has a component in the −Y′-axis direction, and the normal vector of the second surface 127b has a component in the + Y′-axis direction. An external electrode 125 is formed on the surface of the base plate 120 a on the −Y′-axis side, and a wiring electrode 128 is formed on the first surface 127 a and the second surface 127 b of the castellation 127 and the side surface of the bonding material 140. Has been. The external electrode 125 and the wiring electrode 128 are formed of the same electrode layer, and the external electrode 125 and the extraction electrode 132 of the piezoelectric vibrating piece 130 a are electrically connected to each other through the wiring electrode 128.

  FIG. 2B is a plan view of the base plate 120a. No electrode is formed on the bonding surface 122 on the + Y′-axis side of the base plate 120a. In the castellation 127, the wiring electrode 128 is formed after the base plate 120a is joined to the piezoelectric vibrating piece 130a.

  FIG. 2C is a plan view of the base plate 120a on which the external electrode 125 and the ground terminal 126 are shown. FIG. 2C shows the external electrode 125 and the ground terminal 126 that are formed on the surface of the base plate 120a on the −Y ′ axis side through the base plate 120a from the + Y ′ axis side of the base plate 120a. Yes. The external electrode 125 is formed so as to be in contact with the castellation 127, and the ground terminal 126 is formed including a corner portion of the base plate 120a where the castellation 127 is not formed. Further, the external electrode 125 and the ground terminal 126 are formed so as to be in contact with the short side and the long side of the piezoelectric vibrating piece 120a without any gap.

  A bonding material used for a piezoelectric device may be affected by heat such as solder used for mounting on a printed circuit board or the like, and the sealing in the piezoelectric device may be broken. In the piezoelectric device 100, the first surface 127a whose normal vector has a component in the −Y′-axis direction is formed wider than the second surface 127b, so that the solder is the piezoelectric vibrating piece 130a and the base plate 120a. It is hard to reach between. Therefore, it is possible to suppress the influence of solder on the bonding material 140 formed between the piezoelectric vibrating piece 130a and the base plate 120a.

<Method for Manufacturing Piezoelectric Device 100>
FIG. 3 is a flowchart showing a method for manufacturing the piezoelectric device 100. Hereinafter, the manufacturing method of the piezoelectric device 100 will be described with reference to FIG.

  In step S101, a piezoelectric wafer W130 is prepared. The piezoelectric wafer W130 is a wafer formed of a piezoelectric material, and a plurality of piezoelectric vibrating pieces are formed on the piezoelectric wafer W130.

  FIG. 4 is a plan view of the piezoelectric wafer W130. On the piezoelectric wafer W130, piezoelectric vibrating pieces 130a and piezoelectric vibrating pieces 130b are alternately formed in the X-axis direction and the Z′-axis direction. In FIG. 4, a scribe line 142, which is a line for cutting the wafer in step S <b> 107 described later, is indicated by a two-dot chain line at a boundary between adjacent piezoelectric vibrating pieces. The piezoelectric vibrating piece 130 a is connected to the −Z′-axis side on the + X-axis side of the excitation unit 133 and the + Z′-axis side on the −X-axis side, and the piezoelectric vibrating piece 130 b is connected to the + X-axis side of the excitation unit 133. A connecting portion 135 is connected to the + Z′-axis side and the −Z′-axis side of the −X-axis side. Therefore, in the piezoelectric vibrating piece 130a, the extraction electrode 132 is drawn out to the corners on the + Z-axis side on the + X-axis side and on the + Z-axis side on the -X-axis side of the surface on the -Y'-axis side of the frame portion 134. In the vibrating piece 130 b, the extraction electrode 132 is extracted to the + Z′-axis side of the −X′-axis side surface and the −Z′-axis side corner of the −X-axis side of the surface of the frame portion 134. The piezoelectric vibrating piece 130a and the piezoelectric vibrating piece 130b differ only in the formation position of the connecting portion 135, the direction in which the extraction electrode 132 is extracted, and the like, and the electrical characteristics are not changed.

  In step S102, a base wafer W120 is prepared. A plurality of base plates are formed in the base wafer W120 by forming a recess 123 and a through hole 143 penetrating the base wafer W120 in the Y′-axis direction in the base wafer W120.

  FIG. 5 is a plan view of the base wafer W120. In the base wafer W120, base plates 120a and base plates 120b are alternately formed in the X-axis direction and the Z′-axis direction. In FIG. 5, a scribe line 142, which is a line for cutting the wafer in step S107 described later, is indicated by a two-dot chain line at the boundary between adjacent base plates. At intersections of the scribe lines 142 extending in the X-axis direction and the Z′-axis direction, through-holes 143 penetrating the base wafer W120 in the Y′-axis direction are formed every other X-axis direction and Z′-axis direction. . In the base plate 120a, a through hole 143 is formed on the −Z ′ axis side on the + X axis side and the + Z ′ axis side on the −X axis side, and on the + Z ′ axis side and −X axis side on the + X axis side in the base plate 120b. A through hole 143 is formed on the Z ′ axis side. The through hole 143 becomes a castellation 127 after the wafer is cut in step S107 described later.

  6 and 7 are flowcharts showing a method for manufacturing the base wafer W120 shown in FIG. A diagram for explaining each step is shown on the right side of each step shown in FIGS. 6 and 7. 6 and 7 are cross-sectional views corresponding to the BB cross section of the base wafer W120 shown in FIG. Hereinafter, a method for manufacturing the base wafer W120 will be described with reference to FIGS.

  In step S201 of FIG. 6, a wafer formed of a piezoelectric material is prepared. FIG. 6A shows a partial cross-sectional view of a base wafer W120 formed of a piezoelectric material such as quartz. As shown in FIG. 6A, the base wafer W120 prepared in step S201 has a flat surface on the + Y′-axis side and the −Y′-axis side.

  In step S202, the anticorrosion film 150 and the photoresist 151 are formed on both the + Y′-axis side and the −Y′-axis side of the base wafer W120. FIG. 6B is a partial cross-sectional view of the base wafer W120 in which the corrosion-resistant film 150 and the photoresist 151 are formed on the surfaces on the + Y′-axis side and the −Y′-axis side. On the surface of the base wafer W120 on the + Y′-axis side and the −Y′-axis side, first, the anticorrosion film 150 is formed, and further, the photoresist 151 is formed on the surface of the anticorrosion film 150. The corrosion resistant film 150 is formed by performing sputtering or vapor deposition of a metal film on the base wafer W120. The corrosion-resistant film 150 is formed, for example, by forming a film of nickel (Ni), chromium (Cr), titanium (Ti), nickel-tungsten (NiW) or the like on the base wafer W220 as a base, and gold (Au) or silver on the base. It is formed by depositing (Ag) or the like. The photoresist 151 is uniformly applied to the surface of the corrosion resistant film 150 by a technique such as spin coating.

  In step S203, the photoresist 151 is exposed and developed, and the corrosion resistant film 150 is etched. FIG. 6C is a partial cross-sectional view of the base wafer W120 from which the photoresist 151 and the corrosion-resistant film 150 on the −Y′-axis side surface are partially removed. The region where the photoresist 151 and the corrosion-resistant film 150 are removed in step S203 is a region 144 where the through hole 143 is formed on the surface at the −Y′-axis side of the piezoelectric wafer W120. The region 144 is formed in a circular shape and has a diameter of the length WX1.

  In step S204, the base wafer W120 is wet-etched to form part of the through hole 143. FIG. 6D is a partial cross-sectional view of the base wafer W120 in which a part of the through hole 143 is wet-etched. In step S204, the first through hole which is a part of the through hole 143 is formed on the surface at the −Y ′ axis side of the base wafer W120 by performing wet etching of the piezoelectric material exposed in the region 144 formed in step S203. 143a is formed. The piezoelectric material may have anisotropy with respect to etching, and the etching solution is unlikely to circulate deeply into the first through hole 143a of the base wafer W120. Therefore, the first through hole 143a is deep in the + Y ′ axis direction. The diameter of the first through hole 143a is formed so as to become smaller. If the diameter of the aperture is the length WX2, the length WX1 is larger than the length WX2. Further, the depth of the first through hole 143a in the Y′-axis direction is formed at the first distance HY1. The first through hole 143a forms the first surface 127a (see FIG. 2) of the castellation 127 of the base plate.

  In step S205 of FIG. 7, the corrosion resistant film 150 and the photoresist 151 are formed on both main surfaces of the base wafer W120 that are the + Y′-axis side and the −Y′-axis side. Step S205 is a step continuously performed from step S204 of FIG. FIG. 7A is a partial cross-sectional view of the base wafer W120 in which the corrosion-resistant film 150 and the photoresist 151 are formed on the surfaces on the + Y′-axis side and the −Y′-axis side. After step S204, all the corrosion-resistant film 150 and photoresist 151 formed on the base wafer W120 are removed. Again, the corrosion resistant film 150 and the photoresist 151 are formed on the entire surface of the base wafer W120 on the + Y′-axis side and the −Y′-axis side.

  In step S206, the photoresist 151 is exposed and developed, and the corrosion resistant film 150 is etched. FIG. 7B is a partial cross-sectional view of the base wafer W120 in which the photoresist 151 is exposed and developed, and the corrosion-resistant film 150 is etched. The corrosion-resistant film 150 and the photoresist 151 to be removed are a region 145 where the through-hole 143 and a concave portion 123 are formed in the surface on the + Y′-axis side of the base wafer W120. The region 145 is formed in a circular shape having a length WX3 whose diameter is longer than the length WX2.

  In step S <b> 207, the base wafer W <b> 120 is wet-etched, and the concave portion 123 and a part of the through hole 143 are formed. FIG. 7C is a partial cross-sectional view of the base wafer W120 in which a part of the through hole 143 and the concave portion 123 are formed by wet etching. In step S207, the piezoelectric material exposed in the region 145 and the region 146 formed in step S206 is subjected to wet etching, so that the second surface which is a part of the through hole 143 is formed on the surface at the + Y′-axis side of the base wafer W120. A through hole 143b and a recess 123 are formed. The second through-hole 143b is formed so that the diameter of the second through-hole 143b becomes smaller as it becomes deeper in the −Y′-axis direction. The depth of the second through hole 143b in the Y′-axis direction is formed at a second distance HY2 that is shorter than the first distance HY1. By forming the second through hole 143b, a second surface 127b (see FIG. 2) of the castellation 127 of the base plate is formed.

  In step S208, the photoresist 151 and the corrosion resistant film 150 are removed. FIG. 7D is a partial cross-sectional view of the base wafer W120 from which the photoresist 151 and the corrosion resistant film 150 have been removed. FIG.7 (d) is BB sectional drawing of FIG. By removing the photoresist 151 and the corrosion-resistant film 150 in step S208, the base wafer W120 in which the concave portion 123 and the through hole 143 are formed is prepared. The through hole 143 includes a first surface 127a and a second surface 127b, and an intermediate portion 127c is formed between the first surface 127a and the second surface 127b. The diameter of the intermediate portion 127c of the through hole 143 is formed to the length WX2.

  Returning to FIG. 3, in step S103, a lid wafer W110 is prepared. The lid wafer W <b> 110 is formed with a plurality of lid plates 110 on the lid wafer W <b> 110 by forming the concave portions 111 on the surface at the −Y′-axis side.

In step S104, the base wafer W120 and the piezoelectric wafer W130 are bonded to each other. Step S104 is a joining process.
FIG. 8A is a partial cross-sectional view of a wafer in which the piezoelectric wafer W130 and the base wafer W120 are bonded to each other. FIG. 8A shows a cross-sectional view including the BB cross section of FIG. The base wafer W120 and the piezoelectric wafer W130 are bonded via the bonding material 140 to the bonding surface 122 of the base wafer W120 and the surface on the −Y′-axis side of the frame portion 134 of the piezoelectric wafer W130. At this time, the bonding material 140 is not formed on the extraction electrode 132 facing the through hole 143. The base wafer W120 and the piezoelectric wafer W130 are joined such that the piezoelectric vibrating piece 130a and the base plate 130a overlap, and the piezoelectric vibrating piece 130b and the base plate 130b overlap.

In step S105, the piezoelectric wafer W130 and the lid wafer W110 are bonded to each other.
FIG. 8B is a partial cross-sectional view of the wafer in which the piezoelectric wafer W130 and the lid wafer W110 are bonded. The lid wafer W <b> 110 and the piezoelectric wafer W <b> 130 are bonded via the bonding material 140 to the bonding surface 112 of the lid wafer W <b> 110 and the surface on the + Y ′ axis side of the frame portion 134 of the piezoelectric wafer W <b> 130.

In step S106, electrodes are formed on the base wafer W120.
FIG. 8C is a partial cross-sectional view of a wafer in which electrodes are formed on the base wafer W120. In step S106, a ground film 126, an external electrode 125, and a wiring electrode 128 are formed on the base wafer W120 by forming a metal film on the surface at the −Y′-axis side of the base wafer W120 by sputtering or vacuum deposition. This is a wiring formation process. The metal film is formed, for example, by forming a chromium (Cr) film on the base wafer W120 via the mask 147 and further forming a gold (Au) film on the surface of the chromium film. Since the external electrode 125 and the wiring electrode 128 are formed by the same process, the external electrode 125 and the wiring electrode 128 are formed by the same metal film continuously connected to each other. In addition, since the opening on the + Y′-axis side of the through hole 143 is blocked by the frame portion 134 of the piezoelectric wafer W 130, a metal film is formed to spread over the entire through hole 143. Furthermore, a metal film is also formed on the surfaces of the bonding material 140 and the extraction electrode 132 exposed toward the through hole 143. Therefore, in step S106, the external electrode 125, the wiring electrode 128, and the extraction electrode 132 are electrically connected to each other.

  In step S107, the wafer on which the electrode is formed in step S108 is cut by dicing. In step S107, the wafer is cut by a dicing saw (not shown) or the like along the scribe line 142 shown in FIGS. 4, 5, and 8A to 8C. It is formed.

  In the manufacturing method of the piezoelectric device 100, since sputtering or vacuum deposition is not performed on the surface on the + Y′-axis side of the base wafer W120, the manufacturing process is simplified, which is preferable. Further, it is preferable that the amount of the electrode material used can be reduced by not performing sputtering or vacuum deposition on the surface on the + Y′-axis side of the base wafer W120. Further, the through hole 143 of the base plate is formed so that the first surface 127a having a normal vector having a component in the −Y′-axis direction has a larger area than the second surface 127b, and thus the first surface 127a is formed wider. It is easy to deposit a metal film on the through-hole 143 from the −Y′-axis side of the base wafer W120. Further, the second surface 127b is formed so that the area of the second surface 127b is narrow, and the opening on the + Y′-axis side of the through hole 143 is blocked by the frame portion 134 of the piezoelectric vibrating piece, so that the second surface 127b It is also easy to form a metal film. That is, in the piezoelectric device 100, it is easy to form an electrode in the through hole 143.

(Second Embodiment)
The base plate may be made of glass. Since glass has no anisotropy to wet etching, when the base plate is made of glass, the castellation shape is different from the castellation shown in the first embodiment. Hereinafter, a piezoelectric device using a base plate made of glass will be described. Moreover, in the following description, the same number is attached | subjected about the same part as 1st Embodiment, and the description is abbreviate | omitted.

<Configuration of Piezoelectric Device 200>
FIG. 9 is an exploded perspective view of the piezoelectric device 200. The piezoelectric device 200 is mainly composed of a lid plate 110, a base plate 220, and a piezoelectric vibrating piece 130a. In the piezoelectric device 200, the base plate 220 is formed using glass as a base material.

  The base plate 220 has a rectangular shape with long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. The surface on the −Y′-axis side of the base plate 220 is charged to the external electrode 225 (see FIG. 10A) that is an electrode to be electrically connected to a printed circuit board or the like via solder and the piezoelectric device 200. This is a mounting surface on which a ground terminal 226 (see FIG. 10C) for removing static electricity and the like is formed. Further, the bonding material 140 is applied to the bonding surface 222 which is the surface on the + Y′-axis side of the base plate 220 and bonded to the piezoelectric vibrating piece 130 a. Further, the base plate 220 is formed with recesses 223 that are recessed from the joint surface 222 in the −Y′-axis direction, and the base plate 220 has a concave portion 223 inside the base plate 220 on the side surfaces of the four corners. A castellation 227 is formed. The castellation 227 is formed to extend to the long side and the short side of the base plate 220. The castellation 227 includes a first surface 271 that extends outward from the mounting surface toward the bonding surface 222, a second surface 272 that extends outward from the bonding surface 222 to the mounting surface, and has a smaller area than the first surface 271. Between the first surface 271 and the second surface 272, a protruding surface 273 that protrudes outside the base plate 220 from the first surface 271 and the second surface 272 is formed. Each castellation 227 is formed with a wiring electrode 228, and the wiring electrode 228 is electrically connected to the external electrode 225.

  Fig.10 (a) is sectional drawing of CC cross section of FIG. In the piezoelectric device 200, the bonding surface 222 of the base plate 220 and the surface on the −Y′-axis side of the frame portion 134 of the piezoelectric vibrating piece 130a are bonded via the bonding material 140, and the bonding surface 112 of the lid plate 110 and the piezoelectric vibration are bonded. It is formed by joining the surface on the + Y′-axis side of the frame part 134 of the piece 130 a via the joining material 140. The castellation 227 of the base plate 220 has a first surface 271, a second surface 272, and a projection surface 273. The first surface 271 and the second surface 272 are formed as curved surfaces recessed inside the base plate 220, and the projecting surface 273 is formed so as to protrude to the outside of the base plate 220. A ground terminal 226 (see FIG. 10C) and an external electrode 225 are formed on the surface at the −Y′-axis side of the base plate 220, and a wiring electrode 228 is formed on the castellation 227. The wiring electrode 228 is formed of the same electrode layer continuous with the external electrode 225, and electrically connects the external electrode 225 and the extraction electrode 132 formed on the frame portion 134 of the piezoelectric vibrating piece 130a.

  FIG. 10B is a plan view of the base plate 220. No electrode is formed on the surface at the + Y′-axis side of the base plate 220. Further, after the base plate 220 is joined to the piezoelectric vibrating piece 130 a, the wiring electrode 228 is attached to the castellation 227 on the −Z′-axis side on the + X-axis side and the −Z′-axis side on the −X-axis side of the base plate 220. It is formed. The wiring electrode 228 formed on the castellation 227 is formed so as not to contact the short side parallel to the Z ′ axis and the long side parallel to the X axis of the base plate 220. That is, in the XZ ′ plane, the wiring electrode 228 is not formed on the end portion 227a in contact with the short side and the long side of the base plate 220 of the castellation 227, and the glass is external at the end portion 227a of the castellation 227. Is exposed.

  FIG. 10C is a plan view of the base plate 220 on which the external electrode 225 and the ground terminal 226 are shown. FIG. 10C shows the external electrode 225 and the ground terminal 226 that are formed on the surface of the base plate 220 on the −Y ′ axis side through the base plate 220 from the + Y ′ axis side of the base plate 220. Yes. The external electrode 225 is in contact with the castellation 227 and is formed so as not to contact the short side and long side of the base plate 220, and the ground terminal 226 is not in contact with the short side, long side, and castellation 227 of the base plate 220. It is formed as follows.

  In the piezoelectric device 200, the first surface 271 of the castellation 227 of the base plate 220 is formed with a curved surface that is recessed inside the base plate 220, so that when the piezoelectric device 200 is mounted on a printed circuit board or the like, solder is generated. It is preferable because it is difficult to reach the bonding surface 222 and the bonding material 140 is not easily affected by solder. Further, in the piezoelectric device 200, the area of the bonding surface 222 of the base plate 220 is formed wide by forming the area of the second surface 272 narrow. Therefore, it is preferable because the formation area of the bonding material 140 is widened.

<Method for Manufacturing Piezoelectric Device 200>
The piezoelectric device 200 is manufactured according to the flowchart shown in FIG. Hereinafter, a method for manufacturing the piezoelectric device 200 will be described with reference to FIG.

  In step S101, a piezoelectric wafer W230 is prepared. The piezoelectric wafer W230 is a wafer formed of glass, and a plurality of piezoelectric vibrating pieces 130a are formed on the piezoelectric wafer W230.

  FIG. 11 is a plan view of the piezoelectric wafer W230. On the piezoelectric wafer W230, piezoelectric vibrating pieces 130a are formed side by side in the X-axis direction and the Z′-axis direction. In FIG. 11, a scribe line 142 is indicated by a two-dot chain line at a boundary between adjacent piezoelectric vibrating pieces 130 a. The extraction electrode 132 of each piezoelectric vibrating piece 130a shown in FIG. 11 is not electrically connected to the extraction electrode 130a of the other piezoelectric vibrating piece 130a.

  In step S102, a base wafer W220 is prepared. In the base wafer W220, a plurality of base plates 220 are formed in the base wafer W220 by forming a recess 223 and a through hole 243 that penetrates the base wafer W220 in the Y′-axis direction.

  FIG. 12 is a plan view of the base wafer W220. On the base wafer W220, a base plate 220 is formed side by side in the X-axis direction and the Z′-axis direction. In FIG. 12, a scribe line 142 is indicated by a two-dot chain line at a boundary between adjacent base plates. A through hole 243 that penetrates the base wafer W220 in the Y′-axis direction and extends along the X-axis direction and the Z′-axis direction of the scribe line 142 is formed at the intersection of the scribe lines 142 that extend in the X-axis direction and the Z′-axis direction. Is formed. Therefore, through holes 243 are formed at the four corners of each base plate 220. The through hole 243 becomes a castellation 227 after the wafer is cut in step S107 described later.

  13, FIG. 14, and FIG. 15 are flowcharts showing a method for manufacturing the base wafer W220 shown in FIG. A diagram for explaining each step is shown on the right side of each step shown in FIGS. 13, 14, and 15. FIGS. 13, 14, and 15 are diagrams for explaining the respective steps, and are cross-sectional views corresponding to the DD cross section of the base wafer W <b> 220 shown in FIG. 12. Hereinafter, a method for manufacturing the base wafer W220 will be described with reference to FIGS. 13, 14, and 15. FIG.

  In step S211 in FIG. 13, a wafer formed of glass is prepared. FIG. 13A shows a partial cross-sectional view of a base wafer W220 made of glass. As shown in FIG. 13A, the wafer prepared in step S211 is a flat plate in which surfaces on the + Y′-axis side and the −Y′-axis side are formed in a planar shape.

  In step S212, the corrosion resistant film 150 and the photoresist 151 are formed on both the + Y′-axis side and the −Y′-axis side of the base wafer W220. FIG. 13B shows a partial cross-sectional view of the base wafer W220 on which the corrosion resistant film 150 and the photoresist 151 are formed. As illustrated in FIG. 13B, the corrosion resistant film 150 is formed on the surface of the base wafer W <b> 220 on the + Y ′ axis side and the −Y ′ axis side, and the photoresist 151 is formed on the surface of the corrosion resistant film 150. The corrosion resistant film 150 is formed by performing sputtering or vacuum vapor deposition of a metal film on the base wafer W220. The corrosion resistant film 150 is formed, for example, by forming a film of nickel (Ni), chromium (Cr), titanium (Ti), nickel / tungsten (NiW) or the like on the base wafer W220 as a base, and gold (Au) and silver on the base. It is formed by depositing (Ag) or the like. The photoresist 151 is uniformly applied to the surface of the corrosion resistant film 150 by a technique such as spin coating.

  In step S213, the photoresist 151 is exposed and developed. FIG. 13C shows a partial cross-sectional view of the base wafer W220 where the photoresist 151 is exposed and developed. The portions where the photoresist 151 is exposed and developed in step S213 are the recessed region 160 corresponding to the recessed portion 223 (see FIG. 9) on the surface on the + Y′-axis side of the base wafer W220 and the surface on the −Y′-axis side. This is a through region 161 corresponding to the hole 243. In the case where the base material of the base wafer W220 is glass, a region etched by wet etching of the base wafer W220 is widened, so that the recessed region 160 and the through region 161 are formed narrower than the width of the recessed portion 223 and the through hole 243. . In addition, when the width of the through region 161 in the X-axis direction is WA1, it is desirable that the width WA1 be formed small so that the size of the through hole 243 does not become too large.

  In step S214, the corrosion resistant film 150 is etched. FIG. 13D shows a partial cross-sectional view of the base wafer W220 in which the corrosion-resistant film 150 has been etched. In step S214, the recessed region 160 where the photoresist 151 is exposed and developed in step S213 and the corrosion-resistant film 150 in the through region 161 are removed by etching.

  In step S215 of FIG. 14, the base wafer W220 is wet etched. FIG. 14A shows a partial cross-sectional view of the base wafer W220 in which the glass is etched. In step S215, wet etching is performed so that the glass of the recessed region 160 and the through region 161 is dipped in an etching solution, so that the depth of the recessed region 160 and the through region 161 becomes the depth HA1. Since wet etching of glass also etches below the corrosion-resistant film 150, for example, the width WA2 in the X-axis direction of the glass etched in the through region 161 is equal to the width WA1 in the X-axis direction of the through region 161 (FIG. 13C). ))) Will be wider.

  In step S216, after removing the corrosion resistant film 150 and the photoresist 151 on the surface at the + Y′-axis side of the base wafer W220, the corrosion-resistant film 150 is formed again on the surface at the + Y′-axis side of the base wafer W220. A photoresist 151 is formed on the surface. FIG. 14B shows a partial cross-sectional view of the base wafer W220 in which the corrosion-resistant film 150 and the photoresist 151 are formed on the surface at the + Y′-axis side. The corrosion resistant film 150 and the photoresist 151 are formed on the entire surface of the base wafer W220 on the + Y′-axis side.

  In step S217, the photoresist 151 is exposed and developed. FIG. 14C shows a partial cross-sectional view of the base wafer W220 in which the photoresist 151 on the surface at the + Y′-axis side is exposed and developed. The portion of the photoresist 151 exposed and developed in step S217 is a through region 162 corresponding to the through hole 243 on the surface on the + Y′-axis side. Similar to the recessed region 160 and the through region 161, the base wafer W <b> 220 has a region that is etched by wet etching, so the through region 162 is formed narrower than the width of the surface of the through hole 243 on the + Y′-axis side. Further, the width of the penetrating region 162 in the X-axis direction is defined as a width WA3.

  In step S218, the corrosion resistant film 150 is etched. FIG. 14D shows a partial cross-sectional view of the base wafer W220 in which the corrosion-resistant film 150 has been etched. In step S218, the corrosion resistant film 150 formed in the through region 162 is etched away.

  In step S219 of FIG. 15, the base wafer W220 is wet etched. FIG. 15A shows a partial cross-sectional view of a base wafer W220 obtained by wet etching glass. In step S219, the exposed glass of the penetrating region 161 and the penetrating region 162 is wet etched by being immersed in an etching solution, and the depth of the penetrating region 161 becomes the depth HA3 and the depth of the penetrating region 162 becomes the depth HA2. Formed as follows. The depth HA3 of the penetrating region 161 is a total value of the depth HA1 (see FIG. 14A) and the depth HA2. As a result of the wet etching, the width in the X-axis direction of the glass wet-etched in the through region 162 is the width WA5, and the width in the X-axis direction of the glass wet-etched in the through region 161 is the width WA4. The width WA5 is larger than the width WA3 (see FIG. 14C), the width WA4 is larger than the width WA2 (see FIG. 14A), and the width WA4 is larger than the width WA5.

  In step S220, the corrosion resistant film 150 and the photoresist 151 are removed. FIG. 15B shows a partial cross-sectional view of the base wafer W220 from which the corrosion-resistant film 150 and the photoresist 151 have been removed. In the base wafer W <b> 220 in FIG. 15B, a recess 223 is formed in each base plate 220. Further, the thickness of the glass at the position where the through hole 243 is formed is the thickness HA4.

  In step S221, the through hole 143 is formed by sandblasting. FIG. 15C is a partial cross-sectional view of the base wafer W220 in which the through holes 243 are formed by sandblasting. In step S221, the through hole 243 is penetrated by the sand blast that blows the abrasive on the surface at the −Y′-axis side of the base wafer W220, and the projection surface 273 is formed. FIG.15 (c) is sectional drawing of the DD cross section of FIG.

  Returning to FIG. 3, in step S103, a lid wafer W110 is prepared. The lid wafer W <b> 110 is formed with a plurality of lid plates 110 on the lid wafer W <b> 110 by forming the concave portions 111 on the surface at the −Y′-axis side.

In step S104, the base wafer W220 and the piezoelectric wafer W230 are bonded to each other. Step S104 is a joining process.
FIG. 16A is a partial cross-sectional view of a wafer in which the piezoelectric wafer W230 and the base wafer W220 are bonded to each other. FIG. 16A shows a cross-sectional view including the DD cross section of FIG. The base wafer W <b> 220 and the piezoelectric wafer W <b> 230 are bonded via the bonding material 140 to the bonding surface 222 of the base wafer W <b> 220 and the surface on the −Y ′ axis side of the frame portion 134 of the piezoelectric wafer W <b> 230. At this time, the bonding material 140 is not formed on the extraction electrode 132 facing the through hole 243. Further, FIG. 16A shows that the extraction electrode 132 is not formed on the scribe line 142.

In step S105, the piezoelectric wafer W230 and the lid wafer W110 are bonded to each other.
FIG. 16B is a partial cross-sectional view of the wafer in which the piezoelectric wafer W230 and the lid wafer W110 are bonded. The lid wafer W <b> 110 and the piezoelectric wafer W <b> 230 are bonded via the bonding material 140 to the bonding surface 112 of the lid wafer W <b> 110 and the surface on the + Y′-axis side of the frame portion 134 of the piezoelectric wafer W <b> 230.

In step S106, electrodes are formed on the base wafer W220.
FIG. 16C is a partial cross-sectional view of a wafer in which electrodes are formed on the base wafer W220. Step S106 is a wiring in which a ground film 226, an external electrode 225, and a wiring electrode 228 are formed on the base wafer W220 by forming a metal film on the −Y′-axis side surface of the base wafer W220 by sputtering or vacuum deposition. It is a forming process. The metal film is formed, for example, by forming a chromium (Cr) film on the base wafer W220 via the mask 148 and further forming a gold (Au) film on the surface of the chromium film. Since the external electrode 225 and the wiring electrode 228 are formed by the same process, the external electrode 225 and the wiring electrode 228 are formed by the same metal film continuously connected to each other. Further, since the opening on the + Y′-axis side of the through hole 243 is blocked by the frame portion 134 of the piezoelectric wafer W230, a metal film is formed on the entire through hole 243. Furthermore, a metal film is also formed on the surfaces of the bonding material 140 and the extraction electrode 132 exposed toward the through hole 243. By this step S106, the external electrode 225, the wiring electrode 228, and the extraction electrode 132 are electrically connected, and a plurality of piezoelectric devices 200 are formed on the wafer. In FIG. 16C, the mask 148 is also disposed on the scribe line 142, and the wiring electrodes 228 of the adjacent piezoelectric devices 200 in the through holes 243 are formed so as not to be electrically connected to each other.

  FIG. 17A is a plan view of the surface at the −Y′-axis side of the base wafer W <b> 220 on which the electrode is formed. The electrode formed on the base wafer W220 is not formed on the scribe line 142 as shown in FIG. Therefore, the ground terminal 226 and the external electrode 225 formed on each base plate 220 are not electrically connected to the ground terminal 226 and the external electrode 225 formed on the adjacent base plate 220. Further, as shown in FIG. 16C, since the wiring electrode 228 and the extraction electrode 132 of the adjacent piezoelectric device 200 are not electrically connected to each other, each piezoelectric device 200 formed on the wafer is different from each other. The piezoelectric device 200 is not electrically connected. Therefore, after the electrodes are formed on the base wafer W220, the probe 149 is applied to the pair of external electrodes 225 formed on each piezoelectric device 200 as shown in FIG. Can be confirmed.

  FIG. 17B is an enlarged plan view of the region 171 in FIG. FIG. 17B shows a part of the mask 148 used in step S106. The mask 148 has a first opening that is an opening for forming the external electrode 225 and a second opening that is an opening for forming the wiring electrode 228 formed in the through hole 243. The first opening and the second opening are connected to each other. The first opening is substantially equal to the planar shape of the external electrode 225, and the second opening has a planar shape that is slightly larger on the side of the through hole 243 than the shape of the XZ ′ plane of the wiring electrode 228 formed in the through hole 243. Have. As shown in FIG. 17B, since the wiring electrode 228 is formed only in a part of the through hole 243, the area of the second opening for forming the wiring electrode 228 is larger than the area of the through hole 243. Is too narrow. The mask 148 also has an opening for forming the ground terminal 226.

  In step S107 of FIG. 3, the wafer on which the electrodes are formed in step S106 is cut by dicing. Dicing is performed along a scribe line 142 by a dicing saw, and individual piezoelectric devices 200 are formed.

  In the manufacturing process of a piezoelectric device, when dicing a wafer, an electrode formed on the piezoelectric device may be caught in a dicing saw and peeled off. In addition, when the electrodes are cut together with the wafer by the dicing saw, the area of the electrodes formed on each piezoelectric device is different for each piezoelectric device due to the dicing deviation, and the crystal impedance (CI) of each piezoelectric device is different. ) There is a problem that the value varies. In the manufacturing method of the piezoelectric device 200, since the wiring electrode 228 is not formed on the scribe line 142 as shown in FIGS. 16C and 17B, the wiring electrode 228 of the piezoelectric device 200 is formed by wafer dicing. There is no influence, and the crystal impedance (CI) value of each piezoelectric device does not vary due to the non-uniformity of the area of the electrode formed on each piezoelectric device.

  Various shapes can be considered for the castellations formed on the base plate. Below, as a modified example of the castellation formed on the base plate, the base plate 320 having a castellation extending in the short side direction from the corner of the base plate, and the short side of the base plate not including the corner of the base plate The base plate 420 having castellations to be formed will be described.

<Configuration of base plate 320>
FIG. 18A is a perspective view of the base plate 320. The base plate 320 is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. The surface on the −Y′-axis side of the base plate 320 is a mounting surface on which the external electrode 325 (see FIG. 18B) and the ground terminal 326 (see FIG. 18B) are formed. Further, the bonding material 140 is applied to the bonding surface 322 which is the surface on the + Y′-axis side of the base plate 320 and bonded to the piezoelectric vibrating piece 130a. In addition, the base plate 320 is formed with recesses 323 that are recessed from the joint surface 322 in the −Y′-axis direction. Thus, a castellation 327 extending from the corner of the base plate 320 in the short side direction is formed. The castellation 327 includes a first surface 371 that extends outward from the mounting surface toward the bonding surface 322, a second surface 372 that extends outward from the bonding surface 322 to the mounting surface, and has a smaller area than the first surface 371, Between the surface 371 and the second surface 372, a first surface 371 and a projecting surface 373 projecting outside the base plate 320 from the second surface 372 are formed. When the base plate 320 is configured as a part of the piezoelectric device, a wiring electrode 328 is formed on each castellation 327 of the base plate 320, and the wiring electrode 328 includes the external electrode 325 and the extraction electrode 132 of the piezoelectric vibrating piece 130a. Is electrically connected.

  FIG. 18B is a plan view of the base plate 320 on which the external electrode 325 and the ground terminal 326 are shown. FIG. 18B shows an external electrode 325 and a ground terminal 326 that are formed on the surface of the base plate 320 on the −Y′-axis side through the base plate 320 from the + Y′-axis side of the base plate 320. Yes. The external electrode 325 is formed in contact with the castellation 327, and the ground terminal 326 is formed so as not to contact the castellation 327. The external electrode 325 is electrically connected to the wiring electrode 328.

  FIG. 18C is a partial plan view of the surface on the −Y′-axis side of the base wafer on which the base plate 320 is formed. FIG. 18C is a view showing a region similar to FIG. 17B, and FIG. 18C and FIG. 17B have different through-hole shapes. FIG. 18C shows a rectangular through hole 343 formed at the intersection of the scribe lines 142 and extending in the Z′-axis direction. Since the through hole 343 extends in the Z′-axis direction, a pair of wiring electrodes 328 formed in one through hole 343 can be formed apart from each other. Therefore, the pair of wiring electrodes 328 are prevented from being in contact with each other and being electrically connected.

<Configuration of base plate 420>
FIG. 19A is a perspective view of the base plate 420. The base plate 420 is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. The surface on the −Y′-axis side of the base plate 420 is a mounting surface on which external electrodes 425 (see FIG. 19B) and ground terminals 426 (see FIG. 19B) are formed. Further, the bonding material 140 is applied to the bonding surface 422 which is the surface on the + Y′-axis side of the base plate 420 and bonded to the piezoelectric vibrating piece 130a. Further, the base plate 420 is formed with recesses 423 that are recessed from the joint surface 422 in the −Y′-axis direction, and the base plate 420 has a short side surface that does not include the corners of the four corners. A castellation 427 formed so as to be recessed inside 420 is formed. The castellation 427 includes a first surface 471 extending outward from the mounting surface toward the bonding surface 422, a second surface 472 extending outward from the bonding surface 422 toward the mounting surface, and having a smaller area than the first surface 471, and a first surface 471. Between the surface 471 and the second surface 472, a first surface 471 and a projecting surface 473 projecting outside the base plate 420 from the second surface 472 are formed. When the base plate 420 is configured as a part of the piezoelectric device, a wiring electrode 428 is formed on each castellation 427 of the base plate 420, and the wiring electrode 428 includes the external electrode 425 and the extraction electrode 132 of the piezoelectric vibrating piece 130a. Is electrically connected.

  FIG. 19B is a plan view of the base plate 420 on which the external electrode 425 and the ground terminal 426 are shown. FIG. 19B shows an external electrode 425 and a ground terminal 426 that are formed on the surface of the base plate 420 on the −Y′-axis side through the base plate 420 from the + Y′-axis side of the base plate 420. Yes. The external electrode 425 is formed so as to contact the castellation 427, and the ground terminal 426 is formed so as not to contact the castellation 327. Further, the external electrode 425 and the ground terminal 426 are not in contact with the short side and the long side of the base plate 420. The external electrode 425 is electrically connected to the wiring electrode 428.

  FIG. 19C is a partial plan view of the surface on the −Y′-axis side of the base wafer on which the base plate 420 is formed. FIG. 19C shows a state in which the −X-axis side half of the base plate 420 and the + X-axis side half of the other base plate 420 are in contact with each other on the base wafer. A scribe line 142 extending in the Z′-axis direction is shown between the two base plates 420. FIG. 19C shows a rectangular through-hole 443 formed in the scribe line 142 extending in the Z′-axis direction and extending in the Z′-axis direction. The through hole 443 is not formed in the scribe line 142 extending in the X-axis direction. Since the through hole 443 extends in the Z′-axis direction, a pair of wiring electrodes 428 formed in one through hole 443 can be formed apart from each other. Therefore, it is suppressed that a pair of wiring electrode 428 contacts and is electrically connected mutually.

  As described above, the optimal embodiment of the present invention has been described in detail. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

  For example, in the manufacturing process of the piezoelectric device 100 shown in FIG. 3, the electrode forming process of step S <b> 106 may be performed before step S <b> 105. In this case, by applying a probe to the external electrode and measuring the frequency of the piezoelectric vibrating piece, a metal is added to or removed from the excitation electrode 131 formed on the surface on the + Y′-axis side of the piezoelectric vibrating piece. The frequency of the resonator element can be adjusted. Therefore, it is possible to easily adjust the frequency of the piezoelectric vibrating piece. In addition, the glass-based base plate shown in the second embodiment is formed by the method shown in FIGS. 6 and 7, and the castellation is formed only on the first surface and the second surface, and the projection The surface may not be formed.

  Furthermore, in the above-described embodiment, the case where the piezoelectric vibrating piece is an AT-cut quartz-crystal vibrating piece has been shown. However, the same applies to a BT cut that vibrates in the thickness-slip mode or a tuning-fork type quartz vibrating piece. Applicable. Further, the piezoelectric vibrating piece can be basically applied not only to a crystal material but also to a piezoelectric material including lithium tantalate, lithium niobate, or piezoelectric ceramic.

DESCRIPTION OF SYMBOLS 100, 200 ... Piezoelectric device 110 ... Lid board 111, 123, 223, 323, 423 ... Recessed part 112, 122, 222, 322, 422 ... Bonding surface 120a, 120b, 220, 320, 420 ... Base board 125, 225, 325 425 ... External electrode 126, 226, 326, 426 ... Earth terminal 127, 227, 327, 427 ... Castellation 127a, 271, 371, 472 ... First face 127b, 272, 372, 472 ... Second face 127c ... Intermediate Portions 128, 228, 328, 428 ... Wiring electrodes 130a, 130b ... Piezoelectric vibrating piece 131 ... Excitation electrode 132 ... Extraction electrode 133 ... Excitation portion 134 ... Frame portion 135 ... Connection portion 136 ... Through groove 140 ... Bonding material 142 ... Scribe line 143, 243 ... Through-hole 143a ... 1st through-hole 143b ... 2nd through-hole 147, 148 ... Mask 149 ... Probe 150 ... Corrosion-resistant film 151 ... Photoresist 227a ... End of castellation 227 273, 373, 473 ... Projection surface W110 ... Lid wafer W120 , W220 ... Base wafer W130, W230 ... Piezoelectric wafer

Claims (6)

A piezoelectric vibrating piece having a pair of excitation electrodes and a pair of extraction electrodes drawn from the pair of excitation electrodes;
A glass or piezoelectric material having a mounting surface having a pair of external electrodes and a bonding surface on which the piezoelectric vibrating piece is disposed, and a pair of castellations recessed inward from a side surface extending from the mounting surface to the bonding surface A base plate made of
A non-conductive bonding material disposed between the piezoelectric vibrating piece and the base plate and bonding the piezoelectric vibrating piece and the base plate;
The pair of castellations includes a first surface extending outward from the mounting surface to the joint surface side, and a second surface extending outward from the joint surface to the mounting surface and having a smaller area than the first surface. Have
The wiring electrode formed on the first surface, the second surface, and the side surface of the bonding material extends from the external electrode to the extraction electrode on the same electrode layer as the external electrode.   2. The piezoelectric device according to claim 1, wherein the pair of castellations includes a projecting surface that protrudes outside the base plate from the first surface and the second surface between the first surface and the second surface. .   The wiring electrode is formed in a central region of the castellation, and the glass or the piezoelectric material is exposed at an end of the castellation where the castellation and a side surface of the base plate are in contact with each other. The piezoelectric device according to claim 1 or 2. The base plate has a rectangular shape having a long side and a short side,
The castellation includes a shape extending only in the short side in the short side direction or a shape extending in the short side direction from a corner where the short side and the long side intersect. The piezoelectric device according to item. In a manufacturing method for manufacturing a piezoelectric device using a base wafer having a plurality of base plates each having a mounting surface on which external electrodes are formed and a joint surface opposite to the mounting surface.
The base wafer is made of glass or a piezoelectric material, and the diameter decreases from the mounting surface to an intermediate portion separated by a first distance, and the diameter increases from the intermediate portion to the bonding surface separated by a second distance shorter than the first distance. Preparing a base wafer having through holes formed therein;
Preparing a piezoelectric wafer having an excitation part having an excitation electrode, a frame part surrounding the excitation part, and an extraction electrode drawn from the excitation electrode to the frame part;
A bonding step of bonding the base wafer and the piezoelectric wafer with a bonding material so that the through hole and the extraction electrode overlap;
A wiring forming step of forming the external electrode and the wiring electrode extending from the external electrode to the extraction electrode through the side surface of the through hole and the side surface of the bonding material;
A method for manufacturing a piezoelectric device comprising: In the wiring formation step, a mask having a first opening corresponding to the external electrode and a second opening corresponding to the wiring electrode narrower than the through hole is disposed on the mounting surface of the base wafer, and sputtering or vacuum is performed. The method for manufacturing a piezoelectric device according to claim 5, wherein the wiring electrode is formed by vapor deposition.